Method and system for measuring turbine shape

ABSTRACT

A method and system for measuring a turbine shape is provided in which an appropriate measurement accuracy can be achieved that is sufficient to prevent a failure to recognize features of shape of a measurement object, with extension of a measurement time suppressed. In a turbine including casings, recesses and protrusions on flange surfaces of the casings are measured at measurement intervals M set on the basis of the entire length L of flange portions in an axial direction, the number of bolts N joining the flange portions, and intervals between the bolts in the axial direction of the flange portions.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention relates to a method and system for measuring aturbine shape.

2. Description of the Related Art

In general, a casing of a turbine including inner and outer casings isdivided into an upper half casing and a lower half casing both having ahalf-split shape, and flange portions of the upper half and lower halfcasings are joined by bolts. The casing houses a diaphragm and the likeincluded in a stationary body, a turbine rotor included in a rotatingbody rotating with respect to the stationary body, and the like.

In periodic inspection and performance improvement work for a turbine,the upper half casing and the lower half casing are separated from eachother for the inspection or work, and after the inspection or work,assembly work is executed. For example, in assembly work in theperformance improvement work in which a seal fin and the like arereplaced to reduce the clearance between a turbine rotor and the sealfin to thereby decrease the amount of steam, i.e., working fluid,flowing through the clearance, the clearance needs to be strictlymanaged to prevent contact between the turbine rotor and the seal fin.

On the other hand, the casing and the like of the turbine operated for along time under high temperature and high pressure are plasticallydeformed, and thus the amount of adjustment for the casing and built-incomponents in the assembly work needs to be accurately predicted. Theprediction of the amount of adjustment needs the amount of movementoccurring when a horizontal surface of the flange portion of thedeformed casing is clamped. Determination of the amount of movementneeds accurate measurement of the amount of deformation of the flangesurface of the casing.

As a technique related to measurement of such a turbine, for example,JP-2013-32922-A discloses a three-dimensional measurement methodincluding a first step of measuring, in measuring dimensions of ameasurement object mainly including a flat surface, a cylinder, and acurved surface, the overall shape using a non-contact coordinatemeasuring machine to generate three-dimensional shape data regarding theoverall shape, a second step of dividing the measurement object into theflat surface, the cylinder, and the curved surface portion and measuringthese portions using a laser tracking non-contact measuring machine anda laser tracking contact measuring machine, a third step of generatingthree-dimensional shape data regarding the curved surface portion on thebasis of data obtained from the laser tracking non-contact measuringmachine in the second step, a fourth step of performing computation onthe flat surface and the cylinder on the basis of data obtained from thelaser tracking contact measuring machine in the second step, a fifthstep of receiving an input of main portion dimensions manually obtained,a sixth step of synthesizing the data obtained in the first, third,fourth, and fifth steps, and a seventh step of creating design data onthe basis of the data obtained in the sixth step.

SUMMARY OF THE INVENTION

In the related art, the laser tracking non-contact coordinate measuringmachine and the laser tracking contact measuring machine are used tomeasure the casing or the like of the turbine as a measurement object.However, in a case where non-contact measurement is performed using atechnique, for example, laser scan, then due to the presence ofobstacles such as casing bolts in the bolt-joined portions of the upperhalf casing and the lower half casing, the measurement may be affectedby shadows of the obstacles, reflection from glossy surfaces, andexternal factors such as illumination and sunlight. This may lead to areduced measurement accuracy. Additionally, in contact measurement, themeasurement needs to be performed at more measurement points to achievethe appropriate accuracy of the shape of the measurement object that isrecognized on the basis of the measurement results. However, anincreased number of measurement points may increase the amount ofmeasurement time, and a power generation loss may enormously increasedue to an increased construction cost attributed to the extendedmeasurement time and operation delay associated with process delay. Onthe other hand, a casual reduction in measurement points may decreasethe accuracy, and thus both measurement accuracy and measurement timeneed to be considered for setting of measurement points.

In light of the above-described circumstances, an object of the presentinvention is to provide a method and system for measuring a turbineshape, in which an appropriate measurement accuracy can be achieved thatis sufficient to prevent a failure to recognize features of the shape ofthe measurement object, with extension of the measurement timesuppressed.

An aspect of present invention includes a plurality of means foraccomplishing the above-described object, and an example of the means isa method for measuring a turbine shape of a turbine including a casinghaving an upper half casing and a lower half casing with respectiveflange portions joined by bolts, a stationary body housed inside thecasing, and a rotating body housed inside the casing and rotating withrespect to the stationary body, the method including measuring, along anaxial direction, recesses and protrusions on respective contact surfacesof the flange portions of the casing disassembled into the upper halfcasing and the lower half casing at measurement intervals predeterminedon a basis of an entire length of the flange portions in the axialdirection, the number of bolts joining the flange portions, andintervals between the bolts in the axial direction of the flangeportions.

According to the aspect of the present invention, the appropriatemeasurement accuracy can be achieved that is sufficient to prevent afailure to recognize the features of the shape of the measurementobject, with extension of the measurement time suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view illustrating an outer casing of a steamturbine illustrated as an example of a turbine, which is disassembledinto a lower half of outer casing and an upper half of outer casing;

FIG. 2 is a perspective view illustrating an inner casing of the steamturbine which is disassembled into a lower half of inner casing and anupper half of inner casing;

FIG. 3 is a diagram schematically illustrating a general configurationof a measuring system;

FIG. 4 is a flowchart illustrating a processing procedure formeasurement processing;

FIG. 5 is a cross-sectional view schematically illustrating a flangeportion of the inner casing;

FIG. 6 is a plan view illustrating an extracted part of the flangeportion of the inner casing;

FIG. 7 is a diagram illustrating a method for measuring a flange surfaceof the lower half of inner casing;

FIG. 8 is a diagram illustrating an extracted part of the flange portionof the lower half of inner casing in detail;

FIG. 9 is a diagram illustrating, as a comparative example, an exampleof measurement results for the flange surface obtained using the relatedart;

FIG. 10 is a diagram illustrating an example of measurement results forthe flange surface according to the present embodiment;

FIG. 11 is a diagram illustrating an example of a flow of steam insidethe casing;

FIG. 12 is a diagram illustrating an example of measurement results forthe flange surface;

FIG. 13 is a diagram illustrating an example of measurement results forthe flange surface;

FIG. 14 is a diagram schematically illustrating a cross section of thelower half of inner casing taken across a surface perpendicular to anaxial direction with the flange surface not displaced in a widthdirection;

FIG. 15 is a diagram schematically illustrating a cross section of thelower half of inner casing taken across the surface perpendicular to theaxial direction with the flange surface slanted inward in the widthdirection; and

FIG. 16 is a diagram schematically illustrating a cross section of thelower half of inner casing taken across the surface perpendicular to theaxial direction with the flange surface slanted outward in the widthdirection.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

Embodiments of the present invention will be described below withreference to the drawings.

First Embodiment

A first embodiment of the present invention will be described withreference to FIGS. 1 to 9.

FIG. 1 is a perspective view illustrating an outer casing of a steamturbine as an example of a turbine, which is disassembled into a lowerhalf of outer casing and an upper half of outer casing. Additionally,FIG. 2 is a diagram illustrating an inner casing of the steam turbine,which is disassembled into a lower half of inner casing and an upperhalf of inner casing.

The steam turbine includes a rotating body including a rotor or thelike, a stationary body including a blade ring or the like including adiaphragm, a blade ring, a packing ring, a dummy ring, or the like, therotating body and the stationary body not being illustrated, and anouter casing 100 and an inner casing 200 including flange portions 21and 31 of an upper casing, i.e., upper half of outer casing 2 and upperhalf of inner casing 12, and flange portions 20 and 30 of a lowercasing, i.e., lower half of outer casing 1 and lower half of innercasing 11, joined by bolts, the rotating body and the stationary bodybeing housed inside the outer casing 100 and the inner casing. Note thata certain type of stationary body is installed outside the outer casing100 or the inner casing 200.

The outer casing 100 is formed by aligning a position of an upper flangesurface 3 of the flange portion 20 of the lower half of outer casing 1with a position of a lower flange surface 4 of the flange portion 21 ofthe upper half of outer casing 2 with the upper flange surface 3 and thelower flange surface 4 placed in contact with each other and facing eachother, and by joining the flange portions 20 and 21 of the lower half ofouter casing 1 and the upper half of outer casing 2 to be clamped byjoint bolts via bolt holes 5 and 9 formed in the respective flangeportions 20 and 21.

Similarly, the inner casing 200 is formed by aligning a position of anupper flange surface 13 of the flange portion 30 of the lower half ofinner casing 11 with a position of a lower flange surface 14 of theflange portion 31 of the upper half of outer casing 12, with the upperflange surface 13 and the lower flange surface 14 placed in contact witheach other and facing each other, and by joining the flange portions 30and 31 of the lower half of outer casing 11 and the upper half of outercasing 12 to be clamped by joint bolts via bolt holes 15 and 19 formedin the respective flange portions 30 and 31.

For accurate and smooth execution of assembly work for such a turbine,i.e., steam turbine, adjusting work, i.e., alignment work, needs to beexecuted through measuring the positions of the stationary body in theouter casing 100 and the inner casing 200 with reference to the rotatingbody adjusted to the correct position. However, in the outer casing 100and the inner casing 200 in the steam turbine operated for a certainperiod, the flange surfaces 3, 4, 13, and 14 may be deformed due to theeffect of creep.

FIG. 5 is a cross-sectional view schematically illustrating the flangeportion of the inner casing. Additionally, FIG. 6 is a plan viewillustrating an extracted part of the flange portion of the innercasing.

As illustrated in FIG. 5 and FIG. 6, in the steam turbine operated for acertain period, when the flange portions 30 and 31 of the lower half ofinner casing 11 and the upper half of inner casing 12 are joinedtogether to be clamped by the joint bolts with the flange surfaces 13and 13 placed in contact with each other and facing each other, theflange surfaces 13 and 14 may be deformed due to the effect of creep orthe like such that protrusion-shaped portions, i.e., protruding portions32, recess-shaped portions, i.e., recessed portions 33, and the like areformed on a planar shape, i.e., designed shape, obtained duringmanufacturing. This also applies to the lower half of outer casing 1 andthe upper half of outer casing 2 of the outer casing 100.

The alignment work for the outer casing 100 and the inner casing 200 asdescribed above requires measurement of the surface shapes of the flangesurfaces 3 and 4 and 13 and 14 in contact with each other, prediction,on the basis of measurement results, of the amount of displacement ofthe casing caused by deformation of the flange surfaces 3, 4, 13, and 14and computation of the appropriate amount of adjustment for thepositions of the stationary body and the like.

Now, the basic principle of the measuring method according to thepresent embodiment will be described.

FIG. 7 is a diagram illustrating a method for measuring the flangesurface of the lower half of inner casing.

Note that, in the present embodiment, the flange surface 13 of the lowerhalf of inner casing 11 among the flange surfaces 3, 4, 13, and 14 ofthe outer casing 100 and the inner casing 200, will be representativelydescribed, but a similar measuring method can be applied to the otherflange surfaces 3, 4, and 14.

As illustrated in FIG. 7, in the present embodiment, measurementintervals M represented by (Equation 1) below are predetermined on thebasis of an entire length L of the flange portion 30 in an axialdirection, the number of bolts, i.e., the number of bolt holes 15, Njoining the flange portion 30, and intervals between the bolts, i.e.,maximum pitch Pma and minimum pitch Pmi, in the axial direction of theflange portion 30, and at intervals equal to or smaller than themeasurement intervals M, the flange surface 13 is measured along theaxial direction, for example, for the inner side and the outer side ofthe lower half of inner casing 11.M=(L/N)×(Pmi/Pma)  (Equation 1)

(Equation 1) described above is experimentally and empiricallydetermined in light of a reduction in the number of measurement pointsaffecting the measurement time and an increase in the number ofmeasurement points affecting measurement accuracy. Measurement of theflange surface 13 based on (Equation 1) allows achievement of anappropriate measurement accuracy sufficient to prevent a failure torecognize features of the shape of the measurement object, withextension of the measurement time suppressed.

FIG. 3 is a diagram schematically illustrating a general configurationof a measurement system according to the present embodiment.

In FIG. 3, a measurement system 300 is used to measure the flangesurfaces 3, 4, 13, and 14 and includes a point probe 301 including aprobe main body 301 a and a rod-shaped probe member 301 b having a baseend fixed to the probe main body 301 a and a tip brought into contactwith the measurement object, e.g., each of the flange surfaces 3, 4, 13,and 14 of the casing 1, 2, 11, and 12, a probe position sensor 302sensing the position and direction of the point probe 301 in apredetermined coordinate system including the casings 1, 2, 11, and 12,and a controller 303 calculating the position of the tip of the probemember 301 b in the coordinate system on the basis of a sensing resultfrom the probe position sensor 302.

The measurement system 300 employs, for example, a method of using laserlight 312 to sense the position and direction of the point probe 301 tothereby measure the position of the tip of the probe member 301 b. Theprobe position sensor 302 as a laser tracker accurately senses aplurality of reference points provided on the probe main body 301 a toallow identification of the position, in the coordinate system, of thetip of the probe member 301 b with the predetermined shape. In otherwords, by acquiring the position, i.e., coordinates, of the tip of theprobe member 301 b in contact with the measurement object, the surfaceposition, i.e., coordinates, of the measurement object can be acquired.Additionally, by replacing the probe member 301 b with probe membershaving different lengths or shapes and updating shape information on theprobe member 301 b used for position computation, an object with a morecomplicated shape can be measured.

The controller 303 sets measurement points, i.e., positions of themeasurement points with which the tip of the probe member 301 b isbrought into contact, on the flange surface 13 along the axial directionat intervals equal to or smaller than the measurement interval Mcomputed in accordance with (Equation 1) described above, and constantlymeasures the position of the probe main body 301 a, that is, theposition of the tip of the probe member 301 b. In a case where adistance between the measurement point and the tip of the probe member301 b is within a predetermined range, the controller 303 notifies, viaa notification device (for example, a speaker 304 or a tablet or a smartwatch connected to the controller 303 wirelessly or by a cable may beused), an operator of the point probe 301 that the tip of the probemember 301 b is close to any of the measurement points. In accordancewith the notification from the notification device, the operatorperforms an operation triggering information acquisition such asdepression of a measurement button, with the tip of the probe member 301b in contact with the surface of the measurement object, which is, inthis case, synonymous with the measurement point, to measure the surfaceshape of the measurement object, i.e., position coordinates of thesurface.

FIG. 4 is a flowchart illustrating a processing procedure formeasurement processing.

As illustrated in FIG. 4, the controller 303 first calculates themeasurement intervals M on the basis of (Equation 1) described above instep S100, and sets the measurement points on the flange surface 13along the axial direction on the basis of the measurement intervals M,in step S110.

Subsequently, the controller 303 acquires, from the probe positionsensor 302, information regarding the position and direction of thepoint probe 301, and calculates and acquires the position coordinates ofthe tip of the probe member 301 b, in step S120. Then, the controller303 determines whether the tip of the probe member 301 b is within therange of a predetermined distance from the measurement point, that is,whether within a range allowable for the measurement points, in stepS130.

In a case where the determination result in step S130 is YES, thecontroller 303 notifies, via the notification device, the operator thatmeasurement is allowed, in step S140. When the operator executesmeasurement processing, that is, processing of acquiring the positioncoordinates with the tip of the probe member 301 b in contact with themeasurement object in step S150, the controller 303 subsequentlydetermines whether the measurement processing has been executed at allthe measurement points, in step S160. In a case where the determinationresult is YES, the controller 303 ends the processing.

Additionally, in a case where the determination result in step S130 isNO or the determination result in step S160 is NO, the processingreturns to step S120.

The advantages of the present embodiment configured as described abovewill be described.

FIG. 8 is a diagram illustrating an extracted part of the lower half ofinner casing in detail.

For example, in a case where the casing or the like of the turbine, asthe measurement object, is measured using a laser tracking non-contactcoordinate measuring machine or a laser tracking contact measuringmachine as in the related art, accurate measurement of the flangeportions is difficult because the flange portions include obstacles suchas joint bolts as illustrated in FIG. 8. Additionally, in a case wherenon-contact measurement is performed using a technique such as laserscan, the measurement may be affected by shadows of the obstacles,reflection from glossy surfaces, and external factors such asillumination and sunlight. This may lead to a reduced measurementaccuracy. On the other hand, a contact measuring instrument or anon-contact measuring instrument may be used to perform detailedmeasurement over a long time in light of conditions such as obstacles.However, the extended measurement time leads to an enormous increase inconstruction cost or power generation loss. Thus, this method is notappropriate for improving the measurement accuracy.

In contrast, according to the present embodiment, in the turbineincluding the casing having the outer casing 100 and inner casing 200respectively including the flange portions 21 and 31 of the upper halfcasing, i.e., upper half of outer casing 2 and upper half of innercasing 12, and the flange portions 20 and 30 of the lower half casing,i.e., lower half of outer casing 1 and lower half of inner casing 11,joined by bolts, the stationary body housed inside the casing, and therotating body housed inside the casing and rotating with respect to thestationary body, recesses and protrusions on the contact surfaces, e.g.,flange surfaces 3, 4, 13, and 14, of the flange portions 20, 21, 30, and31 of the casing disassembled into the upper casing and the lower casingare measured along the axial direction, at the measurement intervals Mpredetermined in accordance with Equation 1 described above on the basisof the entire length L of the flange portion 30 in the axial direction,the number of bolts, i.e., the number of bolt holes, N joining theflange portion 30, and the intervals between the bolts, i.e., maximumpitch Pma and minimum pitch Pmi, in the axial direction of the flangeportion 30. Thus, an appropriate measurement accuracy can be achievedthat is sufficient to prevent a failure to recognize features of theshape of the measurement object, with extension of the measurement timesuppressed.

FIG. 9 and FIG. 10 are diagrams illustrating an example of measurementresults for the flange surface. FIG. 9 is a diagram illustrating, as acomparative example, an example of measurement results obtained usingthe related art. FIG. 10 is a diagram illustrating an example ofmeasurement results according to the present embodiment.

As illustrated in FIG. 9, with increased intervals between themeasurement points, the number of measurement points is reduced, but themeasurement results deviate from the actual shape in some aspects suchas the peak of displacement of the actual shape in the verticaldirection, i.e., Y direction. Thus, this method does not allow thefeatures of the shape of the measurement object to be accuratelyrecognized.

In contrast, as illustrated in FIG. 10, in a case where the measurementintervals determined on the basis of (Equation 1) described above areused for the measurement, the features of the shape of the measurementobject can be accurately recognized with an increase in the number ofmeasurement points suppressed. This indicates that the appropriatemeasurement accuracy can be achieved, with extension of the measurementtime suppressed.

Modified Example of First Embodiment

A modified example of the first embodiment will be described withreference to FIG. 11 and FIG. 12.

In the present modified example, the measurement intervals M areweighted such that the measurement intervals M are smaller at positionsin the outer casing 100 and the inner casing 200 where significantdisplacement is predicted to occur.

FIG. 11 is a diagram illustrating an example of a flow of steam insidethe casing. Additionally, FIG. 12 is a diagram illustrating an exampleof measurement results for the flange surface.

As illustrated in FIG. 11, the displacement of the flange surface tendsto be more significant in a range A in which the inner casing 200 isexposed to hot steam and has high temperature than in the other areaswith lower temperature as illustrated in a range B and a range C in FIG.12. Additionally, in the outer casing 100 and the inner casing 200, thedisplacement of the flange surface tends to be more significant in areassusceptible to restraint by piping and reaction force attributed toelongation. Thus, as represented by (Equation 2) below, a weightvariable Z is introduced such that the measurement intervals M arereduced in areas where the displacement of the flange surface tends tobe significant.M=(L/N)×(Pmi/Pma)×Z  (Equation 2)

The weight variable Z is set to vary on the basis of areal temperatureor any other factor.

The remaining part of the configuration is similar to the correspondingpart of the first embodiment.

The present modified example configured as described above can produceadvantages similar to the advantages of the first embodiment.

Additionally, the measurement intervals M are computed to correspond tothe temperature or any other factor affecting the amount of displacementof the flange surface, thus enabling an increase in measurementaccuracy.

Second Embodiment

A second embodiment of the present invention will be described belowwith reference to FIGS. 13 to 16.

In the present embodiment, the measurement of the flange surface isperformed not only in the axial direction but also in the widthdirection.

FIG. 13 is a diagram illustrating an example of measurement results forthe flange surface. Additionally, FIGS. 14 to 16 are diagramsschematically illustrating a cross section of the lower half of innercasing taken across a surface perpendicular to the axial direction.

As illustrated in FIG. 13, the measurement is performed in the widthdirection of the flange surface at positions such as positions D and Ein the axial direction where the displacement of the flange surface issignificant. With a large amount of displacement of the flange surface,variation in displacement may also be significant in the width directionof the flange surface. The flange portion may be displaced in the widthdirection, and the amount of the displacement is predicted to varydepending on position in the axial direction. On the other hand, atpositions determined to involve a large amount of displacement in a casewhere the flange surface is measured along the axial direction, theamount of displacement is likely to be large in the width direction.Thus, in the present embodiment, the flange surface is measured alongthe width direction at positions such as positions D and E in the axialdirection whether the flange surface is significantly displaced. Thus,compared to a case with no deformation in the width direction asillustrated in FIG. 14, deformation into a shape slanted inward asillustrated in FIG. 15 or deformation into a shape slanted outward asillustrated in FIG. 16 can be recognized, and the amount of thedeformation, i.e., amount of displacement, can be determined.

The remaining part of the configuration is similar to the correspondingpart of the first embodiment.

The present embodiment configured as described above produces advantagessimilar to the advantages of the first embodiment.

Additionally, the flange surface is measured along the width directionat positions where the amount of displacement may vary along the widthdirection in a case where the flange surface is viewed in the widthdirection, thus allowing the measurement accuracy to be increased withextension of the measurement time suppressed.

Addition

Note that the present invention is not limited to the above-describedembodiments and includes various modified examples and combinationswithout departing from the spirits of the present invention. The presentinvention is not limited to a configuration including all of thecomponents described above in the embodiments, and includes aconfiguration in which some of the components are omitted. Some or allof the above-described components, functions, and the like may beimplemented by, for example, being designed using, for example, anintegrated circuit. The above-described components, functions, and thelike may be implemented in software by a processor interpreting andexecuting programs realizing the respective functions.

DESCRIPTION OF REFERENCE CHARACTERS

-   1: Lower half of outer casing-   2: Upper half of outer casing-   3, 4: Flange surface-   5, 9: Bolt hole-   11: Lower half of inner casing-   12: Upper half of inner casing-   13, 14: Flange surface-   15, 19: Bolt Hole-   20, 21, 30, 31: Flange portion-   32: Protruding portion-   33: Recessed portions-   100: Outer casing-   200: Inner casing-   300: Measurement system-   301: Point probe-   301 a: Probe main body-   301 b: Probe member-   302: Probe position sensor-   303: Controller-   304: Speaker-   312: Laser light

What is claimed is:
 1. A method for measuring a turbine shape of aturbine including a casing having an upper half casing and a lower halfcasing with respective flange portions joined by bolts, a stationarybody housed inside the casing, and a rotating body housed inside thecasing and rotating with respect to the stationary body, the methodcomprising: measuring, along an axial direction, recesses andprotrusions on respective contact surfaces of the flange portions of thecasing disassembled into the upper half casing and the lower half casingat a measurement interval predetermined on a basis of an entire lengthof the flange portions in the axial direction, the number of boltsjoining the flange portions, and an interval between the bolts in theaxial direction of the flange portions.
 2. The method for measuring aturbine shape according to claim 1, wherein assuming that M denotes themeasurement interval, L denotes the entire length of the flange portionsin the axial direction, N denotes the number of the bolts, and Pmi andPma denote a minimum value and a maximum value for the interval betweenthe bolts in the axial direction of the flange portion, the measurementinterval M are represented by:M=L/N×(Pmi/Pma).
 3. The method for measuring a turbine shape accordingto claim 1, wherein the recesses and protrusions on the contact surfacesare measured using a point probe including a probe main body and arod-shaped probe member having a base end fixed to the probe main bodyand a tip in contact with a measurement object, the point probe beingconfigured to measure a position of the tip of the probe member in apredetermined coordinate system including the casing.
 4. The method formeasuring a turbine shape according to claim 1, wherein the measurementinterval is further set on a basis of a temperature distribution in thecasing during operation of the turbine.
 5. A measurement system for aturbine including a casing having an upper half casing and a lower halfcasing with respective flange portions joined by bolts, a stationarybody housed inside the casing, and a rotating body housed inside thecasing and rotating with respect to the stationary body, the measurementsystem measuring recesses and protrusions on respective contact surfacesof the flange portions of the casing disassembled into the upper halfcasing and the lower half casing, the measurement system comprising: apoint probe including a probe main body and a rod-shaped probe memberhaving a base end fixed to the probe main body and a tip in contact witha measurement object; a probe position sensor sensing a position and adirection of the point probe in a predetermined coordinate systemincluding the casing; and a controller calculating a position of the tipof the probe member in the coordinate system on a basis of a sensingresult from the probe position sensor, wherein the controller notifies,via a notification device, an operator that the tip of the probe memberis close to one of measurement points, the measurement points being setat an interval equal to or smaller than a predetermined measurementinterval based on an entire length of the flange portions in an axialdirection, the number of bolts joining the flange portions, andintervals between the bolts in the axial direction of the flangeportions and being set along an axial direction on respective contactsurfaces of the flange portions of the casing disassembled into theupper half casing and the lower half casing, in a case where a distancebetween the tip of the probe member and the one of the measurementpoints is within a predetermined range.